Re: [Qemu-devel] [PATCH] Add remove_boot_device_path() function for hot-unplug device

[lijun]

On 04/15/2014 02:04 AM, Andreas Färber wrote:
> Am 13.04.2014 15:24, schrieb Jun Li:
> > Add remove_boot_device_path() function to remove bootindex when hot-unplug
> > a device. This patch fixed virtio-blk/virtio-net/scsi-disk/scsi-generic device.
> > So it has fixed bug1086603, ref:
> > https://bugzilla.redhat.com/show_bug.cgi?id=1086603
> >
> > Signed-off-by: Jun Li <address@hidden>
> > ---
> >   hw/block/virtio-blk.c   |  1 +
> >   hw/net/virtio-net.c     |  1 +
> >   hw/scsi/scsi-disk.c     |  1 +
> >   hw/scsi/scsi-generic.c  |  1 +
> >   include/sysemu/sysemu.h |  2 ++
> >   vl.c                    | 16 ++++++++++++++++
> >   6 files changed, 22 insertions(+)
> >
> > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > index 8a568e5..ecdd266 100644
> > --- a/hw/block/virtio-blk.c
> > +++ b/hw/block/virtio-blk.c
> > @@ -752,6 +752,7 @@ static void virtio_blk_device_unrealize(DeviceState *dev, 
> > Error **errp)
> >       unregister_savevm(dev, "virtio-blk", s);
> >       blockdev_mark_auto_del(s->bs);
> >       virtio_cleanup(vdev);
> > +    remove_boot_device_path(s->conf->bootindex, dev, "/address@hidden,0");
> >   }
> >   
> >   static Property virtio_blk_properties[] = {
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 33bd233..520c029 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -1633,6 +1633,7 @@ static void virtio_net_device_unrealize(DeviceState *dev, 
> > Error **errp)
> >       g_free(n->vqs);
> >       qemu_del_nic(n->nic);
> >       virtio_cleanup(vdev);
> > +    remove_boot_device_path(n->nic_conf.bootindex, dev, "/address@hidden");
> >   }
> >   
> >   static void virtio_net_instance_init(Object *obj)
> > diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
> > index 48a28ae..f7303e8 100644
> > --- a/hw/scsi/scsi-disk.c
> > +++ b/hw/scsi/scsi-disk.c
> > @@ -2156,6 +2156,7 @@ static void scsi_destroy(SCSIDevice *dev)
> >   
> >       scsi_device_purge_requests(&s->qdev, SENSE_CODE(NO_SENSE));
> >       blockdev_mark_auto_del(s->qdev.conf.bs);
> > +    remove_boot_device_path(s->qdev.conf.bootindex, &dev->qdev, NULL);
> This ...
What's your meaning of "This ..." ? Do you mean to modify it as you show 
in the following ?
Modify it as following, code will be safer. So agree.
> >   }
> >   
> >   static void scsi_disk_resize_cb(void *opaque)
> > diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
> > index 8d92e0d..22b9752 100644
> > --- a/hw/scsi/scsi-generic.c
> > +++ b/hw/scsi/scsi-generic.c
> > @@ -390,6 +390,7 @@ static void scsi_destroy(SCSIDevice *s)
> >   {
> >       scsi_device_purge_requests(s, SENSE_CODE(NO_SENSE));
> >       blockdev_mark_auto_del(s->conf.bs);
> > +    remove_boot_device_path(s->conf.bootindex, &s->qdev, NULL);
> ... and this is not fully right.
>
> Here you probably want DeviceState *dev = DEVICE(s) and then use dev in
> place of &s->qdev.
>
> And for the above:
>
> static void scsi_destroy(SCSIDevice *dev)
> {
>      SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
>
>      scsi_device_purge_requests(&s->qdev, SENSE_CODE(NO_SENSE));
>      blockdev_mark_auto_del(s->qdev.conf.bs);
> }
>
> castling names into:
>
> static void scsi_destroy(SCSIDevice *sdev)
> {
>      DeviceState *dev = DEVICE(sdev);
>      SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, sdev);
>
>      scsi_device_purge_requests(sdev, SENSE_CODE(NO_SENSE));
>      blockdev_mark_auto_del(sdev->conf.bs);
>      remove_boot_device_path(sdev->conf.bootindex, dev, NULL);
> }
>
> or similar. Inline DEVICE(...) would also be possible.
Ok, agree with you. Using DEVICE(...), the code will be more safe. 
Thanks for your good suggestions.
> >   }
> >   
> >   static int scsi_generic_initfn(SCSIDevice *s)
> > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> > index ba5c7f8..f7ad1e2 100644
> > --- a/include/sysemu/sysemu.h
> > +++ b/include/sysemu/sysemu.h
> > @@ -193,6 +193,8 @@ void rtc_change_mon_event(struct tm *tm);
> >   
> >   void add_boot_device_path(int32_t bootindex, DeviceState *dev,
> >                             const char *suffix);
> > +void remove_boot_device_path(int32_t bootindex, DeviceState *dev,
> > +                             const char *suffix);
> >   char *get_boot_devices_list(size_t *size, bool ignore_suffixes);
> >   
> >   DeviceState *get_boot_device(uint32_t position);
> > diff --git a/vl.c b/vl.c
> > index 9975e5a..8aaa1d6 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -1184,6 +1184,22 @@ void add_boot_device_path(int32_t bootindex, DeviceState 
> > *dev,
> >       QTAILQ_INSERT_TAIL(&fw_boot_order, node, link);
> >   }
> >   
> > +void remove_boot_device_path(int32_t bootindex, DeviceState *dev,
> > +                             const char *suffix)
> > +{
> > +    FWBootEntry *i;
> > +
> > +    if (bootindex == -1) {
> > +        return;
> > +    }
> > +
> > +    QTAILQ_FOREACH(i, &fw_boot_order, link)
> > +        if (i->bootindex == bootindex) {
> > +            QTAILQ_REMOVE(&fw_boot_order, i, link);
> This looks dangerous... You are returning out of the loop below, which
> looks OK, but still QTAILQ_FOREACH_SAFE() would make me more comfortable
> reading this.
ok, agree, I will submit a update version later.
> > +            return;
> > +        }
> > +}
> > +
> >   DeviceState *get_boot_device(uint32_t position)
> >   {
> >       uint32_t counter = 0;
> What I haven't checked yet is whether there might be more places, e.g.
> in spapr code since recently, that need these calls while at it.
I am not familiar with ppc. So when you find that needs these calls, 
please add comments. Thanks a lot.

Best regards,
Jun Li
>